Torpedo depth control system



May 31, 1960 s. KOWALYSHYN ETAI- 2,938,436

TORPEDO DEPTH CONTROL SYSTEM Filed Jan. 19, 1954 2 Sheets-Sheet 1 l2 SEAPRESSURE n \1 l5 l6 l3 6 l6 g I? Q: '8 6 4 4 j g as 23 g as & g ///r i4/ l-m E v '4 3a SERVO AMP.

DEPTH RATE INVENTORS.

STEPHEN KOWALYSHYN THOMAS A. DALY LEONARD S. JONES WILLIAM O. OSBONCHARLE8 O. BEATTY u/ wrw 2622M ATTORNEYS 2 Sheets-Sheet 2 May 31, 1960s. KOWALYSHYN ET AL TORPEDO DEPTH CONTROL SYSTEM Filed Jan. 19, 1954TORPEDO DEPTH CONTROL SYSTEM Stephen Kowalyshyn, Sharon, Thomas A. Daly,Swarthm ore, Leonard S. Jones, Sharon, and William O. Osbon, Pittsburgh,Pa., and Charles G. Beatty, Arcadia, Calif., assignors, by mesneassignments, to the United Statesof America as represented by theSecretary of the Navy Filed Jan. 19, 1954, Ser. No. 405,058

7 Claims. (Cl. 114-25) The present invention relates to torpedo depthcontrol systems, and has more particular reference to such controlsystems having anticipating depth control charactenstics.

Stable control in depth of present day torpedoes is commonly achieved byintroducing into the control systems, in addition to a depth componentcorresponding to deviation of torpedo depth from set depth (desiredrunning depth), an anticipation component corresponding to the speed atwhich the torpedo is approaching or departing from set depth. Priordepth control systems of the above type have generally employed ahydrostat for depth determination and a pitch-angle-indicating pendulumfor providing the anticipation component. Such a pendulum arrangement,however, has the inherent disadvantage of being responsive to allacceleration forces With the result that it does not provide a reliableanticipation component. L

The present invention avoids the disadvantages associated with theseprior depth control systems by providing means for directly obtainingthe rate of change of torpedo depth irrespective of the accelerationforces to which the torpedo is subjected. For example, the rate ofchange of depthis measured, in one form of the present invention, by therelative displacement of a hydrostat-operated shaft damped with anattached dashpot Whose reaction force on the shaft is proportional tothe velocity of the shaft. Synchros, energized from the torpedo powersupply, are utilized to convert the movements of the depth and depthrate hydrostat shafts into electrical signals indicative of the deptherror and the rate of change of depth, and are introduced into the depthchannel of a servo amplifier to actuate the torpedo depth controlsurfaces in accordance with the electrical sum of the signals to thusbring the torpedo to the desired running depth with minimum huntingthereabout.

In accordance with'th'e foregoing, it is an object of the presentinvention to provide a torpedo depth control system having anticipatingdepth control characteristics.

Another object of the invention is to provide a torpedo depth controlsystem as in the foregoing which is insensitive 1 to the variousextraneous accelerationsto which'the torpedo may be subjected.

. A further object of the invention is to providega torpedo dept hcontrol system having anticipating depth control characteristics.whereinthe anticipation. component depth. V p Still a further object of theinvention is to provide a torpedo depth control system, havinganticipating depth control characteristics, which is simpleinconstruction, which re quires a minimum of precision in its manufacisderived directly from therate of'change of torpedo :ture,"'whi'chnecessitates simple and relatively few adjustments for proper operation,and which is comprised of essentially similar components. 7 c Anotherobject of the .invention is to provide an accurate and reliable torpedodepth control system having 7 i members "ice anticipating depth controlcharacteristics, as in the foregoing, wherein depth and depth ratecomponents are derived from an undamped hydrostat and a clampedbydrostat, the movements of which are utilized to operate electricalsyncho means in a manner to produce an elec-- trical signal which is afunction of depth error (displacement from a desired depth) and rate ofchange of tailed description had in conjunction with the annexeddrawings wherein:

Fig. 1 illustrates in diagrammatic form one arrange ment of the presentinvention;

Fig. 2 schematically illustrates a depth control circuit employing thehydrostat and synchro assembly shown in Fig. l; 1 a

Fig. 3 schematically illustrates a modified arrangement for convertingthe movements of the hydrostat shafts into servo amplifier controlsignals;

Fig. 4 illustrates in schematic form a modified arrangement of thedamping means of the present invention; and

Fig. 5 illustrates a modified arrangement for drivably' connecting thesynchro shaft and hydrostat shaft.

Referring now to the drawings, more particularly to the modification ofFig. 1, there is illustrated a hydrostat assembly 10 comprising achamber 11 communi cated to sea pressure through an inlet port 12 andcoinmunicated with a first hydrostat chamber 13 through openings 14having formed therearound a valve seat 15. Hydrostat chamber 13 iscommunicated with a second hydrostat chamber 16 by an opening 16'.Disposed in the hydrostat chambers '13 and 16 are hydrostat bel' lows,17 and 18 respectively, each of said bellows being sealed at its lowerend to the bottom walls of the hydrostat chambers. Secured to the endwalls of the bellows 17 and 18 are operating shafts, 19 and 20respectively, operating shaft 19 being extended at its upper end, asshown, and having attached thereon a valve member 21 for sealinglyengaging valve seat 15 under conditions hereinafter described. Disposedwithin the hydrostat bellows 17 and 18 are compression springs, 22 and23 respectively, the springs abutting the end walls of the bellows attheir upper ends andvcon'tacting members 24, 25, respectively, at theirlower ends, said being adjustably secured within openings formed in thelower end walls of chambers 13 and 1 6, as by threading, wherebytoadjust the compression ,of springs 22 and 23. Shafts 19 and 20 haveformedon their lower ends teeth constituting racks 19 and 20-, Bellows17 and its associated elements comprise what may be termed the depthrate hydrostat, while bellows 18 and its associated elements comprisethe depth hydrostat. It is to be understood that the depthratehyd-rostat is basically a depth hydrostat which, however, by meansof damping as. later described, lags in its response to depth changesand displaces at a rate corresponding to the rate of change of depth.

A first synchro, broadly designated as 26 and comprising a stator 27 anda rotor 28, is adapted to be operated in a manner to produce an outputsignal which is propor- Patented May 31, 1960;

3 tional to the rate of change of torpedo depth. To this end, synchrostator 27 is drivably engaged with rack 19. as by means of a drive shaft29 and a gear 30, while rotor 28 of synchro 26 is drivably engaged withthe rack 20' as by means of a drive shaft 31 and a gear 32, whereby thedifferential rotation between stator 27 and rotor 28 will be determinedby the differential movement of hydrostat shafts 19 and 20. Shaft 19 ofthe depth rate hydrostat bellows 17 is connected, as by means of a link33, to the plunger 34 of a dashpot assembly 35. Dashpot assembly 35,which may comprise any conventional dashpot assembly, is shown forpurposes of illustration only, as a chamber 36 having its opposite endscommunicated as by a conduit 37 in which is placed an adjustable orificevalve 38. Chamber 36 and conduit 37 are, in the conventional manner,filled with a suitable damping fluid, the arrangement being such thatthe reaction force on plunger 34 is proportional to the velocity of theplunger in chamber 36.

A second synchro 39, which is adapted to provide an output signal thatis a function of depth, comprises a rotor 40 and stator 41. Rotor 40 isdrivably engaged with the rack 20 as by means of a drive shaft 42 and agear segment 43,while stator 41 of synchro 39 is fixed to some portionof the torpedo body structure 44, whereby the differential rotation ofrotor 40 and stator 41 will be determined by the movement of shaft 20 ofdepth hydrostat bellows 18.

Referring now to Fig. 2 wherein there is illustrated in schematic form adepth control circuit employing the hydrostat and synchro assembly shownin Fig. 1, there is provided within the torpedo a voltage source 45which is electrically connected to the rotor 40 of depth synchro 39.This synchro, which may be a synchro generator, may have its statorleads electrically connected to the stator of a synchro differentialgenerator 47, the latter'having its rotor leads connected to the statorof depth rate synchro 2-6, which may be a synchro control transformer.The output from the rotor of synchro transformer 26 is fed into a servoamplifier and actuator 49 to control the torpedo depth control surfacesin accordance with the signals fed thereto.

The operation of the present depth control system is as follows: Uponentrance of the torpedo intothe water, sea pressure will be exerted onhydrostat bellows 17 and 18 by water flowing through inlet port 12, andopenings 14 into chamber 13 and into chamber 16 through opening 16'.The'compression of bellows 18, and hence the inment of torpedo depthfrom set depth, such set depth a being fixed by angular adjustment ofeither stator 46, or

rotor 48 as shown, of differential synchro generator 47. The outputsignal from differential synchro generator 47 is modified according tothe relative angular displacement of stator 27 and rotor 28 of synchrocontrol transformer 26, which as previously stated, is a function of therate of change of torpedo depth, whereby the electrical signal fed into:servo amplifier 49 for actuating the torpedo con: trol sunfaces willcorrespond to a summation of torpedo depth error and rate of change oftorpedo depth.

Differential synchro generator 47 in association with the illustratedhydrostat'and synchro assembly provides a convenient system forautomatic steering and depth setting, for by well-known and conventionaltechniques, not shown, it may be remotely controlled before torpedolaunching, or additionally during a torpedo run, to preselect a setdepth (normal torpedo running depth) during target search, or to providefor scheduled control of steering in depth during target search, orautomatic steering in depth during homing attack. Should it be desired,however, merely to preselect a set depth, this may be effected by forrotational adjustment of stator 41 of synchro 39 whereby to accomplishmanual depth setting, and

differential synchro generator 47 may thus be omitted and the output ofdepth synchro 3-9 fed directly into rate synchro26.

. The spring constant of bellows assembly 17 and the relative positionsof valve seat 15 and valve member 21 are made such that upon the torpedoexceeding a predetermined depth, valve member 21 will move into sealingengagement with valve seat 15 whereby to prevent the application ofexcessive pressures to bellows 17 and 18 and thus prevent damagethereto.

stantaneous displacement of shaft 20 from its normal of stator 27 androtor 28 of synchro 26 will be dependent upon the instantaneousdifferential displacementof 'hydrostat shafts 19 and 20. It will beapparent that the instantaneous difierential displacement of shafts 19and 20 will be a function of the damping force exerted on shaft 19 bydashpot assembly 35, which damping force acts to oppose movement ofshaft 19, and hence such damping force is a function of the rate ofchange of pressure acting on bellows 17, or, in other words, a functionof the rate of change of torpedo depth. It is clear, there fore, thatthe instantaneous angular displacement of stator 27 and rotor 28 ofsynchro 26 will be a function of the rate of change of torpedo depth.The output from synchro generator 39 is applied to the differentialsynchro generator 47, and the currents in and the voltages between theoutput conductors of differential generator 47 will, in the cenventionalmanner, be determined by the relative angular displacement of rotor 48and stator 46 of differential synchro generator 47, whereby theelectrical signal fed to the synchro control transformer 26, i.e., thedepth rate synchro, will be a function of the displace- Referring now toFig. 3, there is illustrated a modified arrangement for convertinghydrostat shaft motion into proportional electrical signals, on1y thehydrostat shafts and the electro-mechanical conversion components beingshown for the sake of clarity. Synchro 50, in this modification, may bea synchro control transformer comprising a rotor 51 and a stator 52which operates, in full accordance with well-known characteristics ofsuch a synchro, to yield an electrical signal proportional to the sineof the difference between the angle defined by the stator voltages andthe angle of displacement between its rotor and stator. Rotor 51 isdrivably engaged with the rack 53' on depth hydrostat shaft 53,corresponding to the hydrostat shaft 20 of Fig. 1, as by means of thegear 54, whereby the rotation of rotor 51 will be proportional to thesea pressure acting on the hydrostat bellows associated with shaft 53. Amechanical differential 55 is provided in this modification and may beof the type comprising a pair of independently rotatable shafts 56 and56, interconnected by 1 gaged with the rack 58' on depth rate hydrostatshaft 58,

corresponding to hydrostat shaft 19 in Fig. 1, as by the gear 54, anddifferential shaft 56 is drivably connected to rotor 51 of synchro 50,whereby the rotation of shaft 56' will be ,afunction of torpedo depthwhile the rotation of shaft 56fwillbe determined by the movement ofdamped hydrostat shaft 58. Thus, the angular displacement of'differential gear body 57 will be a function of the rate of change oftorpedo depth. Differential gear body 57 is drivingly engaged withstator 52 of synchro 50 as by suitable driving means diagrammaticallyillustrated at 59. It will be apparent from the above, that theelectrical signal delivered bysynchro 50 will be a summation function oftorpedo depth (relative to that corresponding to initial adjustment ofsynchro 50) and rate of change of torpedo depth. The output of synchro50 may be fed either into a differential synchro generator whereby toprovide for automatic depth setting 'as in'the instance of Fig. 2, or,where mechanical means are provided for manual setting as'by initialangular adjustment of stator 52, the output gt synchro' 50 may be feddirectly into the servo amplier 9. a InFig. 4 there is illustrated afurther modification of the present invention, the hydrostat assembly'10 disclosed therein being substantially identical to that shown inFig. 1 with the exception that the separate damping means or dashpotassembly has been eliminated, the damping means being incorporated intothe depath rate hydrostat assembly. Only a portion of the hydrostatstructure is shown in Fig. 4, the remainder of the hydrostat assemblybeing identical with that of Figs. 1 and 2 as shown or as modified byFig. 3. The hydrostat assembly of Fig. 4 differs from that of Fig. 1 inthat separate passages 60 and 61 provide communication between chamber11' and bydrostat chambers 13 and 16 respectively. Passage 60 compriseseither a restricted orifice, as shown, or may incorporate an adjust-ableorifice valve whereby to vary the resistance to flow through passage 60,while passage 61 is unrestricted. Valve member 21, upon the torpedoexceeding a predetermined depth, is, as in the case of Fig. 1, movedinto sealing engagement with valve seat 15 whereby to seal off bothpassages 60 and 61 from sea pressure. In this modification, fluiddamping is provided by the sea water in chamber 13' and restrictedpassage 60. Thus, the diflerential pressure between chambers 11 and 13'or between chambers 13' and 16 will be dependent upon the rate of changeof torpedo depth whereby the instantaneous differential displacement ofhydrostat shafts 19 and 20 will also be a function of the rate of changeof torpedo depth. The operation of this modification is identical tothat of Fig. 1.

Modified means for drivably engaging the synchro 'and/or mechanicaldifferential shafts with the hydrostat shafts is disclosed in Fig. 5wherein a hydrostat shaft 70, which corresponds to either of hydrostatshafts 19 or 20, comprises, in this modification, a pair of spaced clampmembers 71 and 72 fixed to shaft 70. Secured at opposite ends to saidclamping members is a flexible member 73 which may be, for example, anylon cord which engages and is wound around a pulley 74, corresponding,for example, to gear 32 in the modification of Fig. 1, the arrangementbeing such that axial movement of shaft 70 will cause rotation of pulley74. This arrangement has the advantage of reducing friction between theparts and of eliminating back lash which would be inherent in thegearing arrangement of Fig. 1.

From the above it will be apparent that the present invention provides atorpedo depth control system having anticipating depth controlcharacteristics which is simple in construction, owing especially to theessential similarity of the parts, which requires a minimum of precisionof its manufacture, which is easily assembled, which requires a minimumof simple adjustments for proper operation, and which, because of itsinsensitivity to extraneous acceleration forces, provides reliable deptherror and anticipation, or depth rate, components, whereby stable depthcontrol of a torpedo may be achieved at set depth with a minimum ofhunting or oscillating about set depth.

Obviously many modifications of the present invention are possible inthe light of the above teachings. It is therefore to be understood thatwithin the scope of the appended claims the present invention may bepracticed otherwise than as specifically described herein.

What is claimed is:

1. In a torpedo depth control system, a first hydrostat, a first synchrohaving its rotor actuated by said first hydrostat, a second hydrostat,means for damping compressive and expansive movement of said secondhydrostat, and a second synchro having its stator actuated by saidsecond hydrostat and its rotor actuated by said first hydrostat.

The structure-according to claim 1, wherein an excitation voltage isapplied to said first synchro and the output thereof is fed to saidsecond synchro whereby the output of the latter will be a signal whichis a function 7 both of torpedo depth and rate of change of torpedodepth..

' .3. The structure according to claim 2, and a differential synchrogenerator, the output of. said first synchro being fed to saiddifferential synchro generator and the output of the latter being fed tosaid second synchro, whereby depth setting and steering maybe achievedby relative rotation of the rotor and stator of the differential synchrogenerator.

4. In a torpedo depth control system a first hydrostat bellows, a secondhydrostat bellows, said first and second hydrostat bellows being subjectto varying pressure in accordance with torpedo depth, means for dampingcompressive and expansive movement of said second hydrostat bellows, asynchro having rotor and stator members, one said member being driven bymovement of said first hydrostat bellows, mechanical differential meanshaving a pair of input shafts separately driven by movement of saidfirst and second hydrostat bellows and having an output shaft .theangular displacement of which is a function of the instantaneousdiflerential angular displacement of said input shafts, said synchrohaving its other said member driven by said output shaft, whereby saidsynchro, when energized by excitation voltage applied thereto delivers asignal which is a function both of torpedo depth and rate of change oftorpedo depth.

5. In a control system for a body controllably movable into zones ofvarying pressure in a fluid medium, a first fluid pressure responsivedevice, a second fluid pressure responsive device, means for dampingcompressive and expansive movement of said second fluid pressureresponsive device, a first synchro energized by excitation voltageapplied thereto and having its rotor actuated by said first fluidpressure responsive device, a second synchro having its stator actuatedby said second fluid pressure responsive device and its rotor actuatedby said first fluid pressure responsive means, and means to feed theoutput of said first synchro, to said second synchro whereby the outputof the latter synchro will be a signal which is a function both ofpressure and of rate of change of pressure in said fluid medium.

6. In a torpedo depth control system, a pair of pressure responsiveelements, first and second means attached to said pressure responsiveelements and subject to movement thereby in accordance with the pressureexerted on said elements, damping means acting directly upon andresisting the movement of said second 'means in accordance with thevelocity thereof, synchro means responsive to movement of said firstmeans and to damped movement of said second means relative to said firstmeans for providing an electrical signal which is a function of bothtorpedo depth and rate of change of torpedo depth, and valve meansactuated by one of said pressure responsive elements for sealing both ofthe pressure responsive elements against sea pressure at a predetermineddepth.

7. In a control system for a body controllably movable into zones ofvarying pressure in a fluid medium, a pair of pressure responsiveelements, first and second means attached to said pressure responsiveelements and subjected to movement thereby in accordance with thepressure of said fluid medium exerted on said elements, damping meansacting directly upon and resisting themovement of said second means inaccordance with the velocity thereof, and synchro means responsive tomove ment of said first means and to damped movement of' said secondmeans relative to'said first means for pro-- viding an electrical signalwhich is a summation func-- tion of both the pressure on the body andthe rate of" change of pressure on the body, said damping meanscomprising a fluid dashpot assembly having an adjust-- 7 8 ble r tic?val or r ab q nt of tha x e 0f 2M5; .1 Frischc r v Feb.. 4; 1947;damping imposqd upon'movemgnt of said second means, $426,181 pgakig 'eta1. V :Aug. 26, 19' 47.:

' 7. I 2, 5,022 Hanna Au 10,1954 R r nws Cited i the of p t t 23593921 7lgissac'k vNov. -9, 1951 1.

' UNITED STATES PATENTS 5 2 2 705 {Ras sse gt a1. V V 13m .55 1,997,412Fischer Apr. 9, 71935 OTHER REFERENCES 7 I 2,231,715 Gulliks'en Feb. 11,1941 'ServOmeCh-anism Fundamentals, 'pp. -20-24,37 and? 2,412,740 MorganDec- 17', 9 Lauer, Leshick and Matson, authors MqGrgw-Hill;1947.

